N. Nagano, T. Kume, Yasuhiro Utsumi, Naoaki Tashiro, K. Otsuki, M. Chiwa
{"title":"Negligible Response of Transpiration to Late-Summer Nitrogen Fertilization in Japanese Oak (Quercus crispula)","authors":"N. Nagano, T. Kume, Yasuhiro Utsumi, Naoaki Tashiro, K. Otsuki, M. Chiwa","doi":"10.3390/nitrogen3010006","DOIUrl":null,"url":null,"abstract":"Increased atmospheric nitrogen (N) deposition, caused by anthropogenic activities, has various effects on forest ecosystems. Some reports have investigated the responses in tree transpiration to N addition, but few studies have measured the short-term response of mature tree transpiration to N fertilization. This study aimed to clarify the short-term transpiration response in 27-year-old deciduous hardwood trees to an increase in N availability. We established two plot types (control and N-fertilized plots) in Quercus crispula plantation stands in Hokkaido, Northern Japan. We measured sap flow density (SFD; cm3 m−2 s−1) using a thermal dissipation method for three months during the growing season. In the N-fertilized plot, we added 50 kg N ha−1 yr−1 of ammonium nitrate (NH4NO3) to the forest floor in the middle of the measurement periods. For daily mean SFD, we did not find a significant difference between the control and the N-fertilized plots. Leaf N contents did not differ between treatments, implying a negligible difference in physiological responses and transpiration rates. The slight difference between treatments could be because the trees had already foliated before applying the N fertilizer to our deciduous hardwood trees. The present results indicate that the potential increase in N deposition during the growing season does not immediately alter tree transpiration.","PeriodicalId":19365,"journal":{"name":"Nitrogen","volume":"56 1","pages":""},"PeriodicalIF":0.0000,"publicationDate":"2022-02-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Nitrogen","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.3390/nitrogen3010006","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Increased atmospheric nitrogen (N) deposition, caused by anthropogenic activities, has various effects on forest ecosystems. Some reports have investigated the responses in tree transpiration to N addition, but few studies have measured the short-term response of mature tree transpiration to N fertilization. This study aimed to clarify the short-term transpiration response in 27-year-old deciduous hardwood trees to an increase in N availability. We established two plot types (control and N-fertilized plots) in Quercus crispula plantation stands in Hokkaido, Northern Japan. We measured sap flow density (SFD; cm3 m−2 s−1) using a thermal dissipation method for three months during the growing season. In the N-fertilized plot, we added 50 kg N ha−1 yr−1 of ammonium nitrate (NH4NO3) to the forest floor in the middle of the measurement periods. For daily mean SFD, we did not find a significant difference between the control and the N-fertilized plots. Leaf N contents did not differ between treatments, implying a negligible difference in physiological responses and transpiration rates. The slight difference between treatments could be because the trees had already foliated before applying the N fertilizer to our deciduous hardwood trees. The present results indicate that the potential increase in N deposition during the growing season does not immediately alter tree transpiration.
人为活动引起的大气氮沉降增加对森林生态系统有多种影响。一些研究报道了树木蒸腾对N添加的响应,但很少有研究测量成熟树木蒸腾对N施肥的短期响应。本研究旨在阐明27年阔叶树对氮有效性增加的短期蒸腾响应。以日本北海道栎人工林为研究对象,建立了对照区和施氮区两种样地。我们测量了液流密度(SFD;Cm3 m−2 s−1),在生长季节采用散热法,持续3个月。在施氮地块,我们在测量中期向森林地面添加50 kg N ha - 1 yr - 1硝酸铵(NH4NO3)。对于日平均SFD,我们发现对照和施氮地块之间没有显著差异。叶片氮含量在不同处理之间没有差异,这意味着生理反应和蒸腾速率的差异可以忽略不计。处理之间的细微差异可能是因为在对落叶阔叶树施用氮肥之前,树木已经长出了叶子。目前的结果表明,生长季节氮沉降的潜在增加不会立即改变树木的蒸腾作用。